It’s hard to imagine a more fitting habitat for a man who dedicated thirty or more years of his life to environmental work. I’m on a hillside in Transylvania watching His Royal Highness the Prince of Wales measure an oak tree. He is currently circling it with a clkicky tape measure. There is a crowd of people watching him and recording this moment for posterity.

There is a reason that he is measuring this tree: it will be the first entry in a new database called the Remarkable Trees of Romania – reports Charlotte Smith before her long interview with Prince Charles about Transylvania on BBC Radio 4.